This invention relates generally to the field of surgical instruments, and, in particular to a dissector for separating tissue.
Numerous prior art references disclose surgical instruments including dissectors and clamps, wherein the operating end is angled or can be angled with respect to the shaft of the instrument. However, none of the art known to applicant is believed to show or suggest the features of a dissector that can be operated with the tip in a straight direction, and also which can be operated with a forward or distal end of the tip articulated into various angular positions relative to a rear or proximal end of the tip. Prior art devices permit only articulation of the entire operating tip, and usually only at a right angle to the elongate shaft from which the tip extends. The variable articulation of the present invention thereby creates at least two non-collinear working segments that can maintain their cooperation. For example, a variable articulated dissector in accordance with this invention would be able to effectively grip or spread tissue along two non-collinear segments regardless of the angle between the segments. In addition, none of the prior art known to applicant discloses a device which varies the angle between the forward (distal) end and the rear (proximal) end of each jaw forming the tip of the device with relation to the shaft of the dissector by pressing the forward end of the tip against an internal body wall.
For example, in U.S. Pat. No. 5,209,747 (Knoepfler) a surgical instrument with an operating end is disclosed that includes a dissector or a clamp that can be angled with respect to the axis of the shaft of the instrument to a desired angle by rotating a dial. The dial is connected to a rotating shaft, which is coupled to a beveled gear that varies the angle of the entire operating end. The instrument is also capable of providing irrigation, suction and lasing.
U.S. Pat. No. 5,322,505 (Krause, et al.) and U.S. Pat. No. 5,320,635 (Smith, et al.) disclose a surgical cutter with an outer shaft that is curved and a cutting instrument attached to a flexible member within the outer shaft. The angle of the cutting surface is fixed with relation to the axis of the shaft. The instrument facilitates positioning of the cutter without requiring removal from the body and reinsertion but does not provide a variable articulating working head as in the present invention.
U.S. Pat. No. 5,275,608 (Forman, et al.), the entire disclosure of which is incorporated by reference herein, discloses an endoscopic instrument with an operating head member that can be steered within the body by control external to the body cavity, i.e., the angle between the operating member and the shaft of the instrument can be varied, in this case by manipulation of a control member attached to the instrument and external to the body.
Accordingly, a need exists for a dissector which can operate with the tip in a straight direction and which permits the forward or distal end of the tip to be articulated to various angles relative to the proximal end of the tip by pressing the tip against an internal body wall.